Design Lab: Which Surface Provides the Most Friction?
Preston, Spencer, David
Introduction
In our experiment, we wanted to determine which surface would provide the most friction against a cart powered by a fan. We ran the cart on four different surfaces; a metal track, a rubber surface, a hallway, and a table. We wanted to determine the speed of the cart after a distance of sixty centimeters (the cart would go through a photo gate sixty centimeters from the starting point) using LabPro technology. Unfortunately, we were not able to precisely calculate the exact amount of friction present in the system because we didn't know the total amount of energy initially present. However, we were able to determine the kinetic energy present for the cart on each surface as it passed through the photo gate. If a car produced a low amount of kinetic energy on the surfaces, more kinetic energy was lost due to a greater presence of friction. We hypothesized that the track would produce the least amount of friction simply because we felt that its metal surface was the smoothest. We also hypothesized that the rubber surface would provide the most friction because we assumed that its rougher texture would provide plenty of resistance against the cart.
Procedure
We first determined the mass of the cart that we used. Then, we checked the thickness of the "flag" on top of the fan. We set the photogate 60 cm from the starting position of the flag on top of the fan. We connected the photogate to the LabPro data collector to collect our results. Then, we placed a ruler in front of the cart to hold it in place while turning the fan on and then removed the ruler as we pressed start on the LabPro data collector. The LabPro data collector measured the time it took for the flag to pass through the photogate, which measured the velocity at that point. We repeated this procedure 4 more times to reduce statistical error. We repeated this procedure on three different surfaces other than the track, which was the original surface that we tested on. Finally, we measured the average kinetic energy as the cart passes through the photogate for each surface after we had calculated the mass and velocity of the cart. By determining kinetic energy, we were able to determine which surfaces had more or less friction. The surfaces with more kinetic energy had less friction and the surfaces with less kinetic energy had more friction.
Results
Data Table of Average Velocity and Average Kinetic Energy on Four Different Surfaces:
TABLE
RUBBER
HALLWAY
TRACK
Avg. Velocity (m/s)
.39842
.46086
.49268
.50526
Avg. Kinetic Energy (J)
.06132
.0821
.0913
.09878
Figure 1:
This data clearly indicates that the average kinetic energy varies on the different surfaces, with the table producing the least kinetic energy and the track producing the largest amount of kinetic energy on the cart. Thus, the table produces the most amount of friction and the track produces the least amount of friction.
Conclusions
Based on our results, we concluded that the cart rolling on the table produced the most amount of friction out of the four surfaces due to the fact that the cart had the least amount of kinetic energy on the table. The cart on the rubber surface produced the second most amount of friction, the hallway produced the third most amount of friction, and the track produced the least amount of friction. The results were slightly surprising, since we didn't realize that the table's surface provided a significant amount of resistance to the moving cart in comparison with the other surfaces. As for problems encountered, we had to redo all of our data collecting at one point because we didn't place the flag (the piece of tape on top of the cart) exactly 60 centimeters from the photo gate. Because our reference wasn't always exact with every trial, our results were completely skewed. In addition, the cart that we tested wasn't strong enough to roll on certain surfaces like carpets. This also limited the amount of surfaces we could test for friction. Throughout our experiment, we weren't able to calculate the exact friction present in the system; we could only determine that friction was present and surfaces varied in quantities of friction. To improve on this experiment, it would be necessary to calculate the force produced by a fan pushing the cart using some sort of higher-end technology. This would allow us to determine how much energy was available in the system, and we would simply subtract the total energy from the kinetic energy remaining (after the cart ran for 60 cm) to determine the amount of friction present.
Table of Contents
Design Lab: Which Surface Provides the Most Friction?
Preston, Spencer, David
Introduction
In our experiment, we wanted to determine which surface would provide the most friction against a cart powered by a fan. We ran the cart on four different surfaces; a metal track, a rubber surface, a hallway, and a table. We wanted to determine the speed of the cart after a distance of sixty centimeters (the cart would go through a photo gate sixty centimeters from the starting point) using LabPro technology. Unfortunately, we were not able to precisely calculate the exact amount of friction present in the system because we didn't know the total amount of energy initially present. However, we were able to determine the kinetic energy present for the cart on each surface as it passed through the photo gate. If a car produced a low amount of kinetic energy on the surfaces, more kinetic energy was lost due to a greater presence of friction. We hypothesized that the track would produce the least amount of friction simply because we felt that its metal surface was the smoothest. We also hypothesized that the rubber surface would provide the most friction because we assumed that its rougher texture would provide plenty of resistance against the cart.
Procedure
We first determined the mass of the cart that we used. Then, we checked the thickness of the "flag" on top of the fan. We set the photogate 60 cm from the starting position of the flag on top of the fan. We connected the photogate to the LabPro data collector to collect our results. Then, we placed a ruler in front of the cart to hold it in place while turning the fan on and then removed the ruler as we pressed start on the LabPro data collector. The LabPro data collector measured the time it took for the flag to pass through the photogate, which measured the velocity at that point. We repeated this procedure 4 more times to reduce statistical error. We repeated this procedure on three different surfaces other than the track, which was the original surface that we tested on. Finally, we measured the average kinetic energy as the cart passes through the photogate for each surface after we had calculated the mass and velocity of the cart. By determining kinetic energy, we were able to determine which surfaces had more or less friction. The surfaces with more kinetic energy had less friction and the surfaces with less kinetic energy had more friction.
Results
Data Table of Average Velocity and Average Kinetic Energy on Four Different Surfaces:
Figure 1:
This data clearly indicates that the average kinetic energy varies on the different surfaces, with the table producing the least kinetic energy and the track producing the largest amount of kinetic energy on the cart. Thus, the table produces the most amount of friction and the track produces the least amount of friction.
Conclusions
Based on our results, we concluded that the cart rolling on the table produced the most amount of friction out of the four surfaces due to the fact that the cart had the least amount of kinetic energy on the table. The cart on the rubber surface produced the second most amount of friction, the hallway produced the third most amount of friction, and the track produced the least amount of friction. The results were slightly surprising, since we didn't realize that the table's surface provided a significant amount of resistance to the moving cart in comparison with the other surfaces. As for problems encountered, we had to redo all of our data collecting at one point because we didn't place the flag (the piece of tape on top of the cart) exactly 60 centimeters from the photo gate. Because our reference wasn't always exact with every trial, our results were completely skewed. In addition, the cart that we tested wasn't strong enough to roll on certain surfaces like carpets. This also limited the amount of surfaces we could test for friction. Throughout our experiment, we weren't able to calculate the exact friction present in the system; we could only determine that friction was present and surfaces varied in quantities of friction. To improve on this experiment, it would be necessary to calculate the force produced by a fan pushing the cart using some sort of higher-end technology. This would allow us to determine how much energy was available in the system, and we would simply subtract the total energy from the kinetic energy remaining (after the cart ran for 60 cm) to determine the amount of friction present.